PVDD

GVDD

PVDD

BSTN

GND

OUTN

OUTP

GND

GVDD

BSTP

IN_P

IN_N

GND

Control

Speaker

Guard

Gain

Control

Pulse

Width

Modulator

(PWM)

Gate

Drive

Gate

Drive

Overcurrent Detection

DC Detection

Thermal Protection

Voltage Protection

Protection

Control

Diagnostics

Control

Short-to-Ground

Short-to-Power

Shorted Load

Open Load

Preamplifier

PVDD

GVDD

BYP

LDO

Regulator

FAULT

STANDBY

MUTE

SDA

SCL

I C

2

Biases

and

References

TAS5421-Q1

SLOS814C – MARCH 2014 – REVISED JANUARY 2015

www.ti.com

7 Detailed Description

7.1 Overview

The TAS5421-Q1 is a mono analog-input audio amplifier for use in the automotive environment. The design uses

an ultra-efficient class-D technology developed by Texas Instruments, but with features added for the automotive

industry. This technology allows for reduced power consumption, reduced heat, and reduced peak currents in the

electrical system. The device realizes an audio sound system design with smaller size and lower weight than

traditional class-AB solutions.

There are seven core design blocks:

•

PWM

•

Gate drive

•

Power FETs

•

Diagnostics

•

Protection

•

Power supply

•

7.2 Functional Block Diagram

7.3 Feature Description

7.3.1 Analog Audio Input and Preamplifier

The differential input stage of the amplifier cancels common-mode noise that appears on the inputs. For a

differential audio source, connect the positive lead to IN_P and the negative lead to IN_N. The inputs must be

ac-coupled to minimize the output dc-offset and ensure correct ramping of the output voltages. For good

transient performance, the impedance seen at each of the two differential inputs should be the same.

The gain setting impacts the analog input impedance of the amplifier. See Table 1 for typical values.

10

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